This invention relates generally to a protractor and specifically to a protractor design to be used by school age children.
Protractors typically used by children in school comprise a generally flat protractor disc having a straight edge portion and a semi-circular portion having angle indicia on a front surface thereof. In order to draw a particular degree angle it is necessary to use the protractor to mark the apex of the angle and points associated with the legs of the angle. It is then necessary to manipulate the protractor to connect the points to form the particular angle. To measure the number of degrees of a particular angle, it is necessary to extend the lines forming the angle to coincide with the indicia on the protractor.
In U.S. Pat. No. 1,944,812 a protractor is disclosed that includes an arm member that may be pivotally located at various positions for the drawing of angular lines. The outer end portion of the arm member contacts an outer indicia surface of the protractor. This device is relatively complex in design and not particularly suitable for inexpensive manufacture from plastic components.
There is a need for a protractor that facilitates the drawing and measurement of angles and which may be inexpensively manufactured from plastic materials.